A touch panel is a device that detects touch with a finger or the like to specify position coordinates of a position where the touch panel is touched. The touch panel has attracted attention as excellent user interface means. Various types of touch panels such as a resistance film type, an electrostatic capacitive type and the like have been produced.
Generally, the tough panel is made up of a touch screen incorporating a touch sensor, and a detection device that specifies position coordinates where the touch panel is touched, based on a signal from the touch screen.
As one of the electrostatic capacitive type touch panels, there is a projected capacitive type touch panel (e.g., refer to Patent Document 1).
The projected capacitive type touch panel can detect touch even when a front surface side of the touch screen where the touch sensor is incorporated is covered with a protective plate such as a glass plate having a thickness of about several millimeters.
This type of touch panel is excellent in robustness, because the protective plate can be arranged in a front surface. Moreover, the detection of touch is enabled when gloves are worn. In addition, since it has no movable portion, it has a long service life.
The projected capacitive type touch panel generally includes a plurality of row-direction wirings provided so as to extend in a row direction, which configures a first electrode, and a plurality of column-direction wirings provided so as to extend in a column direction, which configures a second electrode. A field change between the row-direction wiring and the column-direction wiring, that is, a change in an inter-wiring capacitance of the row-direction wiring and the column-direction wiring (hereinafter, simply referred to as an inter-wiring capacitance) is detected to thereby specify position coordinates where the touch panel is touched. This detection method is generally called a mutual capacitance detection method (e.g., refer to Patent Document 2).
Moreover, when the touch screen is attached to a display device, a display area of the display device is covered with the row-direction wiring and the column-direction wiring included in the touch screen. In accordance with the arrangement of the wirings, transmission of display light becomes ununiform, or a reflectivity of outside light becomes ununiform, which may cause a moire phenomenon, or may allow wirings to be visually recognized. In order to provide high-quality pictures to a user, a touch screen of which existence is difficult for the user to feel, such as a touch screen in which wirings are difficult to be visually recognized, is more preferable.